Battaglia Rosalia, Vento Maria Elena, Ragusa Marco, Barbagallo Davide, La Ferlita Alessandro, Di Emidio Giovanna, Borzí Placido, Artini Paolo Giovanni, Scollo Paolo, Tatone Carla, Purrello Michele, Di Pietro Cinzia
Department of Biomedical and Biotechnological Science, Section of Biology and Genetics, Giovanni Sichel, University of Catania, Catania, Italy.
IVF Unit, Cannizzaro Hospital, Catania, Italy.
Biol Reprod. 2016 Dec;95(6):131. doi: 10.1095/biolreprod.116.142711. Epub 2016 Nov 9.
Maternal RNAs are synthesized by the oocyte during its growth; some of them are utilized for oocyte-specific processes and metabolism, others are stored and used during early development before embryonic genome activation. The appropriate expression of complex sets of genes is needed for oocyte maturation and early embryo development. In spite of the basic role of noncoding RNAs in the regulation of gene expression, few studies have analyzed their role in human oocytes. In this study, we identified the microRNAs (miRNAs) expressed in human metaphase II stage oocytes, and found that some of them are able to control pluripotency, chromatin remodeling, and early embryo development. We demonstrated that 12 miRNAs are differentially expressed in women of advanced reproductive age and, by bioinformatics analysis, we identified their mRNA targets, expressed in human oocytes and involved in the regulation of pathways altered in reproductive aging. Finally, we found the upregulation of miR-29a-3p, miR-203a-3p, and miR-494-3p, evolutionarily conserved miRNAs, also in aged mouse oocytes, and demonstrated that their overexpression is antithetically correlated with the downregulation of DNA methyltransferase 3A (Dnmt3a), DNA methyltransferase 3B (Dnmt3b), phosphatase and tensin homolog (Pten), and mitochondrial transcription factor A (Tfam). We propose that oocyte miRNAs perform an important regulatory function in human female germ cells, and their altered regulation could explain the changes occurring in oocyte aging.
母源RNA是卵母细胞在生长过程中合成的；其中一些用于卵母细胞特异性过程和代谢，另一些则在胚胎基因组激活之前的早期发育过程中储存和使用。卵母细胞成熟和早期胚胎发育需要复杂基因集的适当表达。尽管非编码RNA在基因表达调控中具有基本作用，但很少有研究分析它们在人类卵母细胞中的作用。在本研究中，我们鉴定了人类减数分裂II期卵母细胞中表达的微小RNA（miRNA）,并发现其中一些能够控制多能性、染色质重塑和早期胚胎发育。我们证明，12种miRNA在高龄育龄女性中差异表达，通过生物信息学分析，我们确定了它们在人类卵母细胞中表达的mRNA靶标，这些靶标参与了生殖衰老中改变的信号通路的调控。最后，我们发现miR-29a-3p、miR-203a-3p和miR-494-3p（进化上保守的miRNA）在老年小鼠卵母细胞中也上调，并证明它们的过表达与DNA甲基转移酶3A（Dnmt3a）、DNA甲基转移酶3B（Dnmt3b）、磷酸酶和张力蛋白同源物（Pten）以及线粒体转录因子A（Tfam）的下调呈负相关。我们提出，卵母细胞miRNA在人类雌性生殖细胞中发挥重要的调节功能，其调节改变可能解释了卵母细胞衰老过程中发生的变化。
